NAACP leaders in Anne Arundel County said yesterday that the county school system has discriminated against black students by suspending and expelling them at higher rates than whites and by failing to provide enough access to high-level academic courses.

Gerald Stansbury, president of the Anne Arundel NAACP, said the 75,000-student system is "limiting the education and employment opportunities for our youth."

Stansbury was joined at a news conference by more than 50 parents, students and politicians to announce that the NAACP and a coalition of parents, educators and other community members had filed a formal complaint with the U.S. Department of Education's Office for Civil Rights. Under the law, filing such a complaint is a requirement before a lawsuit can be pursued.

The announcement coincided with yesterday's 50th anniversary of Brown v. Board of Education, the Supreme Court decision that declared segregation in the nation's public schools unconstitutional. "What is being done today is viewed as a sequel to Brown, 50 years later," said Carl O. Snowden, an Anne Arundel parent and NAACP member. "We have a desegregated school system which has segregated classrooms based on race." Snowden is also special assistant to County Executive Janet S. Owens (D), although he said he was not acting in that role when he joined the complaint.

Specifically, the NAACP officials said, black students are more likely to be enrolled in special education programs and less likely to graduate from a county high school than their white peers.

Anne Arundel Schools Superintendent Eric J. Smith countered with his own news conference. He acknowledged that minority students have lagged in some academic areas. For example, on a reading test given to every sophomore in Anne Arundel, white and Asian students scored above the 60th percentile while African Americans were in the 40th percentile and Latinos in the 41st percentile.

On the SAT, which colleges use in their admissions process, white students at Annapolis High School averaged 1094 last year -- well above the national average of 1026 -- while black students averaged 897. A perfect score on the exam, which measures math and verbal skills, is 1600.

But Smith said he did not believe that racial discrimination was the reason for the achievement gap. "I don't classify it as bias," he said.

Smith came to Anne Arundel two years ago from Charlotte, where he presided over the end of a three-decade battle over student busing that had reached the Supreme Court. "We were able to successfully reduce that gap," Smith said. "I'm very confident that we'll be able to duplicate that here."

After the Brown decision on May 17, 1954, many U.S. school systems, including Anne Arundel's, were slow to come up with a plan to desegregate their campuses. Prince George's County, for example, was declared free of the vestiges of segregation just two years ago after a federal judge ended a 30-year-desegregation lawsuit that had been filed by that county's NAACP branch. The Prince George's system, which is now majority African American, is still carrying out the judge's orders.

The American Civil Liberties Union of Southern California has been one of the most active groups seeking legal and administrative solutions to improve minority achievement in the nation's public schools. Catherine Lhamon, a staff attorney for the group, said complaints of the sort filed by the Anne Arundel group are less common than during the height of the civil rights movement.

Department of Education officials could not be reached to comment yesterday.

The parents and NAACP leaders involved in the Anne Arundel case said their decision to file the complaint was partially precipitated by Smith's removal of Deborah Hall Williams as principal of Annapolis High School in March. Williams was given an administrative job.

Smith had hired Williams, who is black, from Prince George's specifically to help close the achievement gap at the school. But her leadership style irked many parents, and some complained loudly. Williams attended yesterday's news conference but did not talk to reporters.

Racial divisions have been evident in the county from time to time. Last spring, five students at South River High School, which is 93 percent white, were arrested and charged with hate crimes for painting pro-Ku Klux Klan messages in school stairwells and putting neo-Nazi fliers on cars in the parking lot.

Carol S. Parham, who was the county's first black superintendent, received a racially tinged death threat a few years ago after she suggested busing students from mostly-white Mayo Elementary School to an empty wing at the mostly-black Annapolis Middle School while their school was being renovated.

Black parents said they did not believe that Smith has been able to bring to Anne Arundel the kind of academic improvements he made in North Carolina. In Charlotte, Smith established magnet schools and a school-choice program throughout the district, so that students went to the location that best suited their academic needs, not necessarily their neighborhood schools. But Smith has found that budget constraints have made it hard to pay for expensive changes in Anne Arundel.

"I can't comment on the [complaint], but I do understand people's frustrations with a county that's the third-richest county in the state [and] that has such an underperformance of minority students in the school system," said Anne Arundel school board member Eugene Peterson.

Staff writers David A. Fahrenthold and Jay Mathews contributed to this report.